From inside his vehicle that night, Zimmerman, 28, called the police and asked them to come out and investigate what Martin was up to. He had no idea that Martin was staying in the neighborhood with his father and his father's girlfriend and was walking back from the store.
On a recording of the call, Zimmerman could be heard at one point telling the dispatcher that Martin had taken off. "Shit, he's running," Zimmerman said. At almost the same moment, the audio captured him taking off his seat belt, opening the door to his vehicle and getting out to follow the teen.
Authorities have said Martin ran because he was afraid of Zimmerman and that the neighborhood watchman chased him down, confronted him and eventually shot and killed him.
But on Wednesday night's broadcast, Zimmerman changed his story from what he told the dispatcher that night. He also said there was no way Martin was afraid of him. Here's part of the transcript prepared by FOX News:
HANNITY: Why do you think that he was running then?
ZIMMERMAN: Maybe I said running, but he was more --
HANNITY: You said he's running.
ZIMMERMAN: Yes. He was like skipping, going away quickly. But he wasn't running out of fear.
HANNITY: You could tell the difference?
ZIMMERMAN: He wasn't running.
HANNITY: So he wasn't actually running?
ZIMMERMAN: No, sir.
HANNITY: OK. Because that's what you said to the dispatcher, that you thought he was running.
Zimmerman went on to say he was "going in the same direction" as the teen to watch where he was headed but was not "actually pursuing him."
The discrepancies could end up being damaging to his defense. Prosecutors charged him with second-degree murder and said his actions led to a fight and ultimately to Martin's death. He has pleaded not guilty, said the teen attacked him first.
But that wasn't the only inconsistency in his story on Wednesday. He also shifted what he said happened after coming face to face with the teen.
Zimmerman in the past has told authorities some slightly different versions about the encounter. All seem to involve the teen punching him in the nose, knocking him to the ground and getting on top of him.
But in one version, Zimmerman has said the teen repeatedly punched him in the face while he was flat on his back and then slammed his head into the concrete. In another version, he never mentioned the punches, saying only that the teen got on top of him and immediately started to slam his head onto the ground.
Zimmerman told the first version to investigators just hours after the shooting in an interrogation room in Sanford, Fla. The interview was recorded on video and released to the public in recent weeks.
"He ended up on top of me and he just kept punching my face and my head," Zimmerman said in the interrogation. "I got a little bit of leverage and I started to sit up, and he took my head and slammed it into the concrete."
The second version came days later when Zimmerman was taken back to the neighborhood by police investigators to reenact the events of that night. It was also recorded on video and recently released.
"He got on top of me somewhere around here and that's when I started screaming 'help, help' as loud as I could. Oh, that's when he grabbed me — I tried to sit up and that's when he grabbed me by the head and tried to slam my head down," Zimmerman said.
Zimmerman returned to his first version of the story on Wednesday night with Hannity. He said the teen punched him "more than a dozen" times while he was on the ground. Here again is the FOX News transcript:
HANNITY: OK. So after that first hit, what happened next?
ZIMMERMAN: He started bashing my head into the concrete sidewalk. I was -- as soon as he broke my nose, I was -- I started yelling for help. So, I was disoriented. And he started slamming my head into the concrete.
HANNITY: Which is where the lacerations came from?
ZIMMERMAN: Yes, sir.
HANNITY: You said it was like your head was going to explode was a comment that you had given to the police.
ZIMMERMAN: Yes, sir. He continued to punch me in the head.
HANNITY: How many times would you estimate that he punched you?
ZIMMERMAN: Several. More than a dozen.
HANNITY: And hitting you hard.
Zimmerman is free on a $1 million bond. His trial is expected to begin next year.